Device for diluting fibrous stock

ABSTRACT

Device for diluting a fibrous stock that includes a drum and a displacer. A center line of the drum is oriented at at least an angle of about 10° from horizontal. At least one feed opening is structured and arranged to feed the fibrous stock, at least one discharge opening is structured and arranged to discharge the fibrous stock, and the displacer includes a rotor. A drive is coupled to the rotor to transmit necessary energy for dilution.

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] The present application claims priority under 35 U.S.C. § 119 of German Patent Application No. 100 46 169.7, filed Sep. 19, 2000, the disclosure of which is expressly incorporated by reference herein in its entirety.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] The invention relates to a device for diluting a fibrous stock having a drum provided with a displacer, in which a center line of the drum is tilted in reference to horizontal by at least about 10°. The device includes at least one feed opening for the fibrous stock on its upper face and at least one discharge opening on its lower face.

[0004] 2. Discussion of Background Information

[0005] With the aid of such a device, for example, soiled used paper is to be mixed with water and disintegrated. However, it can also be provided for used paper that has already been cleaned or for virgin pulp.

[0006] A process for diluting fibrous stock with a rotating drum having a displacer being used for performing the process is known, e.g., from EP 0 898 012 A1. In most cases, this diluting drum is arranged horizontally, however, in a special case that is depicted, it may be vertical as well. Drums of this type can achieve very positive diluting results, however, they require a constructive expense that is frequently not acceptable. High sagging forces must be taken into account in a horizontal arrangement and the space required is considerable.

SUMMARY OF THE INVENTION

[0007] The present invention provides a device for diluting fibrous stock which can achieve good results while requiring little constructive expense.

[0008] Accordingly, the present invention is directed to device similar in general to the above-described device, in which the displacer is a rotor with a drive that transmits the energy necessary for dilution.

[0009] In the device according to the invention, a relatively voluminous, drum-shaped displacer, sometimes provided with protrusions, is moved in relation to a drum that is generally stationary. In a steep, i.e., approximately vertically positioned drum, the ring-shaped clearance between the rotor and the interior wall of the drum is filled in its entire circumference, in contrast to the horizontally positioned drums, thus allowing a better use of the drum volume. Depending on the way of operation desired the useful filling level can be adjusted in order to control the diluting process, for example. Due to its own weight, the fibrous stock introduced advances slowly from the top towards the bottom, thus being diluted, and is removed from the lower axial end of the drum as a diluted stock.

[0010] Usually, a voluminous axial mixing does not occur so that a complete and non-coincidental processing of the stock introduced can be achieved. This results in a particularly even stock processing. Additionally, this non-mixing described has the advantage that, in the lower part of the diluting device, a dilution can be performed, without the layers positioned above losing their desired high viscosity. However, if a controlled axial mixing is to occur, it can easily be achieved by a carrier positioned correspondingly diagonal to a rotor and/or a braking element in the drum in a very steep arrangement. A mixing that is limited to certain zones is possible as well.

[0011] In arrangements further away from the vertical, e.g., about 45°, the axial mixing occurs automatically. This angle can be modified and/or adjusted for optimization purposes as well.

[0012] In addition to the elimination of high lateral forces, the standing arrangement of this diluting device has a quite decisive advantage when operated empty because it is much easier to empty a standing drum with discharge lying on its bottom as compared to a horizontal drum. Emptying is necessary, for example, for a grade change or during intended stops. Additionally, the vertical arrangement of this diluting device saves floor space, which is advantageous because sufficient height is usually available. Although the charging must then occur at a greater height, as a rule, even the charging of horizontal drums or stock diluting devices requires a plate conveyor.

[0013] The processing of the stock located in the ring channel occurs primarily by means of transverse forces which develop because of the relative motion of the rotor and the drum surrounding it. In order to intensify the transverse forces, both the rotor and the interior wall of the drum may be provided with protrusions, thus, e.g., by means of entrainers or brake rails. Preferably, they are arranged such that a radial distance between parts motioned in relation to one another remains at all times. In this manner, the danger of damage or blockages of the device is reduced decisively.

[0014] Accordingly, the present invention is directed to a device for diluting a fibrous stock that includes a drum and a displacer. A center line of the drum is oriented at at least an angle of about 10° from horizontal. At least one feed opening is structured and arranged to feed the fibrous stock, at least one discharge opening is structured and arranged to discharge the fibrous stock, and the displacer includes a rotor. A drive is coupled to the rotor to transmit necessary energy for dilution.

[0015] In accordance with a feature of the invention, an upper face is in an upper region of the drum and a lower face is in a lower region of the drum. The at least one feed opening can be arranged on the upper face and the at least one discharge opening may be arranged on the lower face.

[0016] The center line of the drum can be oriented at an angle of no more than about 45° from vertical. Further, the center line of the drum may be oriented at an angle of no more than about 30° from vertical.

[0017] According to another feature of the instant invention, the drum can be stationarily mounted.

[0018] Moreover, according to the present invention the device may include that the rotor and the drum are concentrically arranged in relation to each other.

[0019] Further, a core of the rotor can be drum-shaped. Additionally, or alternatively, a core of the rotor has an oval design.

[0020] In accordance with the invention, the drum and the rotor can be arranged to form a ring-shaped gap between a core of the rotor and an interior wall of the drum. Further, the ring-shaped gap can have a minimum width of no more than about 500 mm. Still further, the ring-shaped gap has a substantially constant width.

[0021] According to a further feature of the invention, entraining rails may be coupled to an exterior of the rotor. The entraining rails may be structured to axially extend at least about 200 mm along the exterior of the rotor. Further, the entraining rails can be structured to radially extend no more than about 100 mm from the exterior of the rotor, and, preferably, the entraining rails are structured to radially extend no more than about 50 mm from the exterior of the rotor. The entaining rails may be structured and arranged with a shape and size so that, when diluting soiled used paper, adhesion of plastic films or tape is prevented. Further, the entraining rails can be structured and arranged to be tilted relative an axis of the rotor.

[0022] The device can also include brake rails on an interior of the drum. A radial extension of the brake rails may be no more than about 100 mm, and, preferably, a radial extension of the brake rails may be no more than about 50 mm. The brake rails can be structured and arranged with a shape and size so that, when used for diluting soiled used paper, adhesion or spinning of plastic films or tape is prevented. Further, the brake rails may be arranged obliquely to an axial direction.

[0023] The drum and the rotor can be arranged to form a gap having a minimum width of at least about 30 mm. Further, the gap can have a minimum width of at least about 100 mm.

[0024] A ring-shaped gap may be formed between a core of the rotor and an interior wall of the drum, and the device can further include feed points structured and arranged to feed diluting water into the ring-shaped gap. The feed points may be located in a lower section of the drum. Further, the feed points can be located in a lowermost one-third of the drum.

[0025] In accordance with the instant invention, the device can include a ring-shaped surface which extends below a lowermost edge of the drum which can be structured and arranged to form a discharge opening. The ring-shaped surface may include a slide ring, and a magnitude of the discharge opening is variable by axially moving the slide ring. A magnitude of the discharge opening can be at least one of enlargable and reduceable by respectively lifting and lowering the drum.

[0026] According to a still further feature of the present invention, a top of the rotor is structured and arranged to be supported and driven. The rotor can be supported and driven only at the top.

[0027] The rotor and the drum may be arranged to form a ring chamber having a volume in a lowermost one-third which is larger than a volume in either of an uppermost one-third and a middle one-third of the ring chamber.

[0028] In accordance with another feature of the invention, the drum can be positioned substantially vertically.

[0029] The drum may include circumferential protrusions extending from an interior surface. Further, the drum can include at least two circumferential protrusions extending from the interior surface, which are axially spaced from each other, and, in a region of the rotor which corresponds to a region between the axially spaced circumferential protrusions, at least one helically arranged entraining rail can be formed on the rotor. The helically arranged entraining rail can be arranged to form a plurality of threads.

[0030] A drivable rotor shaft may be coupled to the rotor to rotate the rotor. The rotor shaft can be coupled to a bottom of the rotor, and a least a portion of the rotor shaft extends into the drum. Further, mixing wings can be coupled to the rotor shaft, and the mixing wings may include a diagonal edge on a front side structured and arranged to deflect contaminants.

[0031] The rotor can include a cylindrical section and conical section. The conical section may be arranged such that, in a direction toward the discharge opening, a gap width between the rotor and the drum increases. Further, the conical section can be attached below the cylindrical section.

[0032] In accordance with yet another feature of the present invention, a water feed pipe can extend into an interior of the rotor, and the rotor may include at least one water discharge hole coupled to the water feed pipe to add water to the fibrous stock between the rotor and the drum. The at least one water discharge hole can be arranged in a lower portion of the rotor. Further, the at least one water discharge hole can be arranged in a lowermost one-third of the rotor.

[0033] Other exemplary embodiments and advantages of the present invention may be ascertained by reviewing the present disclosure and the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The present invention is further described in the detailed description which follows, in reference to the noted plurality of drawings by way of non-limiting examples of exemplary embodiments of the present invention, in which like reference numerals represent similar parts throughout the several views of the drawings, and wherein:

[0035]FIG. 1 schematically illustrates a side view of the device according to the invention;

[0036]FIG. 2 schematically illustrates a top view of the device according to the invention;

[0037]FIG. 3 schematically illustrates a sectioned side view of an embodiment of the invention;

[0038]FIG. 4 schematically illustrates a top view of the embodiment depicted in FIG. 3;

[0039]FIG. 5 schematically illustrates a side view of another embodiment of the device;

[0040]FIG. 6 schematically illustrates a top view of the embodiment depicted in FIG. 4;

[0041]FIG. 7 schematically illustrates a side view of still another embodiment of the invention;

[0042]FIG. 8 illustrates a detailed view of a specially embodied mixing zone;

[0043]FIG. 9 illustrates a top view of another variant of the invention;

[0044]FIG. 10 illustrates a side view of still another variant of the invention;

[0045]FIG. 11 illustrates a top view of the device depicted in FIG. 10;

[0046] FIGS. 12-14 illustrate side views of additional embodiments of the invention; and

[0047]FIG. 15 illustrates a side view of a diluting device positioned diagonally.

DETAILED DESCRIPTION OF THE PRESENT INVENTION

[0048] The particulars shown herein are by way of example and for purposes of illustrative discussion of the embodiments of the present invention only and are presented in the cause of providing what is believed to be the most useful and readily understood description of the principles and conceptual aspects of the present invention. In this regard, no attempt is made to show structural details of the present invention in more detail than is necessary for the fundamental understanding of the present invention, the description taken with the drawings making apparent to those skilled in the art how the several forms of the present invention may be embodied in practice.

[0049]FIG. 1 shows the general structure and the function of a diluting device according to the invention. In the illustrated embodiment, drum 1 may be substantially vertical, and it may be preferred to orient drum 1 precisely vertically, to accept fibrous stock F. Feed openings 3 are provided on its upper face, through which fibrous stock F and at least partially water W necessary for dilution are introduced. Optionally, additional diluting water W′ can be introduced at certain points through the side wall of drum 1. For this purpose, a feed point 8 is drawn in schematically. Within the drum, a rotor 2 is provided that is embodied or formed in the shape of a drum. The concentric arrangement of rotor 2 and drum 1 provides the advantage that radial forces essentially cancel each other, thus impacting the support of rotor 2 only to a very small extent and stress the symmetrical drum 1 to a lesser degree as well. The radial forces are very high when highly consistent fibrous stock is processed. Due to the symmetry and concentration, a width f (see FIG. 2) of the ring-shaped gap (or clearance) located between rotor 2 and drum 1 is constant over its circumference. Width f is measured between the interior wall of drum 1 and the core of rotor 2. Thus, the transverse force is approximately even over the entire circumference as well, and the constructive volume of the device is optimally utilized for mechanical processing.

[0050] Rotor 2 is provided with a multitude of entraining rails 6. The number and size of these entraining rails can be determined by simple experiments, in which it must be taken into account that fibrous stock F1 provided in the ring-shaped gap is entrained in the necessary fashion, i.e., does not merely slide off the exterior wall of the rotor 2. However, it has previously been observed that such rotors can be sufficient without any such entraining rails. This depends on the prevailing conditions, in particular on the viscosity of the highly consistent fibrous stock. In many cases, wall friction effects are already sufficient, or cause at least a great portion of the stock movement. On its interior wall, the drum 1 can be provided with brake rails 7, again in order to increase the relative motion and thus the transverse forces in fibrous stock F. Regarding their shape and number, reference is made here to the statements concerning entraining rails 6.

[0051] Subsequent to the introduced fibrous stock F being mixed with water and diluted in the desired fashion, this stock can be removed from the inside of the drum 1 via one or more discharge openings 4 at the bottom. The embodiment implied here has a discharge opening 4 in the shape of a ring surface clear of any ribs onto which contaminants could adhere. Drum 1 is then held by laterally mounted supports 12. Between a lower axial opening of drum 1 and a floor plate 13 arranged at a distance therefrom, a sliding ring 14 can be moved up and down such that a discharge opening 4 can be enlarged or reduced in the axial direction. This construction is very advantageous for operating the diluting device, particularly when used paper is to be processed that has spinning contaminants, such as, e.g., plastic films. However, other embodiments are possible as well as discussed below. It is also useful to provide a control device to ensure, e.g., the desired throughput through the diluting device by appropriate modifications of discharge (or exit) openings 4. The diluted fibrous stock F2 can run off without any problems through exit opening 4, in particular when its viscosity was lowered further by means of additional diluting water W′ in the lower region. In other cases, discharge opening 4 can be designed such that highly consistent fibrous stock can pass through. Rotor 2 is placed in rotational motion by a drive 5 in order to introduce sufficient diluting energy into the fibrous stock.

[0052]FIG. 2 shows a similar device in a top view, again drawn only schematically. It is discernible that the core of the rotor 2 is drum-shaped, i.e., has a circularly round layout. Entraining rails 6 and braking rails 7 meet at a distance a and thus do not engage. The position of entraining and/or braking rails on the circumference is different from that of the device shown in FIG. 1.

[0053]FIG. 3 shows a device according to the invention in a technically more detailed fashion, without it being a construction drawing. Again, drum 1 and rotor 2 positioned concentrically to it are discernible. The core of rotor 2 includes a circular cylinder onto which an entraining rail 6 is mounted. In the example shown here, they are directed strictly axially, do not exceed the overall height of rotor 2, and are staggered. This design is very easy to produce. At the lower part of drum 1, several discharge openings 4, which are adjustable in their size, are left clear, and fibrous stock F2 can run off into a ring channel 11. At the lower end of the drum, rotor 2 is provided with a disc 9 having a sealing device 10 and, thus, is sealed from the bottom of drum 1. Such structural element are known per se and are only implied here.

[0054]FIG. 4 shows a top view of a similar apparatus to the one shown in FIG. 3. This view demonstrates that several feed points 8 for diluting water W′ are distributed over the circumference of drum 1. They are positioned such that the fibrous stock is diluted in the lower part of the device only and can subsequently drain off. In contrast to the one in FIG. 3, drum 1 here is provided with brake rails 7 positioned on the inside. Their radial extension d, i.e., their protrusion in relation to the internal wall of the drum, is advantageously no greater than for necessary the purpose of the brake rails. This way, spinning and wear can be prevented best. The same is true for the radial extension c of entraining rails 6 over the core of rotor 2.

[0055] Another possibility for adjusting the device according to the invention to its requirements is shown in FIG. 5. In this regard, rotor 2 is staggered in reference to the center line of drum 1 by eccentricity e. The asymmetrical design results in a working volume with a narrower and a wider distance from the rotor to the interior wall of the drum, causing the fibrous stock to move alternately between the wider swelling space and the narrower shearing space.

[0056] With respect to rotor 2, this figure shows a variant, namely that it is supported both on the bottom and at the top. For this purpose, for example, upper bearing point 17 can be mounted in a lid. This lid then includes feed opening 3. A rotor supported in this manner can better compensate the forces present, in particular when uneven horizontal forces occur due to eccentricity. Another possibility for introducing the diluting water is shown as well. Here, the diluting water is guided into the interior of the rotor via a feeding pipe 16 and then introduced into the stock through holes 15. In FIG. 5, no entraining rails are provided on the rotor. In this manner, discharge openings 4 are elongated holes with adjustable sliding plates 18 in the lower part of drum 1. Such structures are considerably simpler than those according to FIG. 1.

[0057] The top view of FIG. 6 shows an embodiment similar to the one in FIG. 5. However, rotor 2 is provided with entraining rails 6. Feed points 8′ for the diluting water are discernible as well. This figure shows a drum without any brake rails, which can be quite practical. In general, however, they are necessary. They can be distributed unevenly over the circumference, e.g., more of them at the narrower distance from the rotor and fewer or even none at the wider distance. Thus, the holding time of the fibrous stock in the welling space can be reduced.

[0058]FIG. 7 shows an embodiment with diagonal entraining rails 6′ and diagonal brake rails 7′ oriented diagonally with respect to the longitudinal axis of drum 1 and rotor 2. The transporting motion of the fibrous stock from the top to the bottom is supported thereby. Such a process can be performed differently for certain zones as well. It may be advantageous to create axially limited, local mixing zones in which the radial mixing of the fibrous stock processed in the ring chamber is enhanced. For this purpose, protrusions 19 are to be provided on the interior side of drum 1, preferably extending over the entire circumference, as shown in FIG. 8. In cooperation with the motion of rotor 2, the axially limited, local mixing can be created at these protrusions 19, particularly when the rotor is provided with helically constructed entraining rails 6″ in this axial region.

[0059]FIG. 9 shows the device according to the invention in a highly schematic fashion, in which a rotor 2′ with an elliptical core is centrally positioned in a circular cylindrical drum 1. Such a rotor has an enhanced entraining effect in the circumferential direction, thus it may not require entraining rails. Otherwise, this embodiment has similar advantages to those shown in FIGS. 5 and 6. However, potential problems caused by overly strong radial forces to be compensated by bearings are avoided.

[0060] Since it is frequently desirable to perform another dilution of the fibrous stock sliding down from the top in the lower part of the device according to the invention, in which a larger volume is advantageous, this lower region can be enlarged such that, as shown in FIG. 10, a rotor shaft 21 with a considerably smaller diameter is provided in reference to the one of the sections positioned thereabove. Then, this part of the device serves less for diluting but rather for mixing the diluted fibrous stock, highly consistent up to then, with the introduced diluting water W′. Optionally, these regions can have mixing wings 20 which, according to FIG. 11, have a diagonal edge on the front side for deflecting any contaminants that may be present.

[0061] A variant of the embodiment shown in FIG. 10 is conceivable according to FIG. 12 as well, namely that the lower part of the rotor is embodied as a cone-shaped shaft 21′. In order to avoid the expense arising from the penetration of the rotor shaft through the floor of the drum 1, the entire rotor 21 can also be held in a bearing 17 positioned on top and be driven from the top, as shown in FIG. 13.

[0062] Another possibility of creating an enlarged volume at the bottom of the drum for the more strongly diluted fibrous stock is shown in FIG. 14. Thus, the cylindrical part of drum 1′ can be continued at its Lower end in the form of a radially enlarged ring chamber 23 as well. Furthermore, FIG. 14 shows the possibility of draining the diluted stock from ring chamber 23 via a discharge opening 4 belonging to a tangential exit.

[0063] In the form shown in FIG. 15, the center line of the drum is positioned at an angle α of about 45° from vertical. This version is more advantageous than a vertical arrangement, e.g., when a stronger axial mixing of the fibrous stock F1, located in the diluting process, is desired. Sometimes the introduction is easier as well. One possible advantage is the lower construction height.

[0064] It is noted that the foregoing examples have been provided merely for the purpose of explanation and are in no way to be construed as limiting of the present invention. While the present invention has been described with reference to an exemplary embodiment, it is understood that the words which have been used herein are words of description and illustration, rather than words of limitation. Changes may be made, within the purview of the appended claims, as presently stated and as amended, without departing from the scope and spirit of the present invention in its aspects. Although the present invention has been described herein with reference to particular means, materials and embodiments, the present invention is not intended to be limited to the particulars disclosed herein; rather, the present invention extends to all functionally equivalent structures, methods and uses, such as are within the scope of the appended claims. 

What is claimed:
 1. A device for diluting a fibrous stock comprising: a drum and a displacer, wherein a center line of said drum is oriented at at least an angle of about 10° from horizontal; at least one feed opening structured and arranged to feed the fibrous stock; at least one discharge opening structured and arranged to discharge the fibrous stock; said displacer comprising a rotor; and a drive coupled to said rotor to transmit necessary energy for dilution.
 2. The device in accordance with claim 1, further comprising an upper face in an upper region of said drum and a lower face in a lower region of said drum, wherein said at least one feed opening is arranged on said upper face and said at least one discharge opening is arranged on said lower face.
 3. The device in accordance with claim 1, wherein the center line of said drum is oriented at an angle of no more than about 45° from vertical.
 4. The device in accordance with claim 3, wherein the center line of said drum is oriented at an angle of no more than about 30° from vertical.
 5. The device in accordance with claim 1, wherein said drum is stationarily mounted.
 6. The device in accordance with claim 1, wherein said rotor and said drum are concentrically arranged in relation to each other.
 7. The device in accordance with claim 1, wherein a core of said rotor is drum-shaped.
 8. The device in accordance with claim 1, wherein a core of said rotor has an oval design.
 9. The device in accordance with claim 1, wherein said drum and said rotor are arranged to form a ring-shaped gap between a core of said rotor and an interior wall of said drum.
 10. The device in accordance with claim 9, wherein said ring-shaped gap has a minimum width of no more than about 500 mm.
 11. The device in accordance with claim 9, wherein said ring-shaped gap has a substantially constant width.
 12. The device in accordance with claim 1, further comprising entraining rails coupled to an exterior of said rotor.
 13. The device in accordance with claim 12, wherein said entraining rails are structured to axially extend at least about 200 mm along said exterior of said rotor.
 14. The device in accordance with claim 12, wherein said entraining rails are structured to radially extend no more than about 100 mm from said exterior of said rotor.
 15. The device in accordance with claim 12, wherein said entraining rails are structured to radially extend no more than about 50 mm from said exterior of said rotor.
 16. The device in accordance with claim 12, wherein said entaining rails are structured and arranged with a shape and size so that, when diluting soiled used paper, adhesion of plastic films or tape is prevented.
 17. The device in accordance with claim 12, wherein said entraining rails are structured and arranged to be tilted relative an axis of said rotor.
 18. The device in accordance with claim 1, further comprising brake rails on an interior of said drum.
 19. The device in accordance with claim 18, wherein a radial extension of said brake rails is no more than about 100 mm.
 20. The device in accordance with claim 18, wherein a radial extension of said brake rails is no more than about 50 mm.
 21. The device in accordance with claim 18, wherein said brake rails are are structured and arranged with a shape and size so that, when used for diluting soiled used paper, adhesion or spinning of plastic films or tape is prevented.
 22. The device in accordance with claim 18, wherein said brake rails are arranged obliquely to an axial direction.
 23. The device in accordance with claim 1, wherein said drum and said rotor are arranged to form a gap having a minimum width of at least about 30 mm.
 24. The device in accordance with claim 23, wherein said gap has a minimum width of at least about 100 mm.
 25. The device in accordance with claim 1, wherein a ring-shaped gap is formed between a core of said rotor and an interior wall of said drum, and said device further comprises feed points structured and arranged to feed diluting water into said ring-shaped gap, wherein said feed points are located in a lower section of said drum.
 26. The device in accordance with claim 25, wherein said feed points are located in a lowermost one-third of said drum.
 27. The device in accordance with claim 1, further comprising a ring-shaped surface which extends below a lowermost edge of said drum and which is structured and arranged to form a discharge opening.
 28. The device in accordance with claim 27, wherein said ring-shaped surface comprises a slide ring, and a magnitude of said discharge opening is variable by axially moving said slide ring.
 29. The device in accordance with claim 27, wherein a magnitude of said discharge opening is at least one of enlargable and reduceable by respectively lifting and lowering said drum.
 30. The device in accordance with claim 1, wherein a top of said rotor is structured and arranged to be supported and driven.
 31. The device in accordance with claim 30, wherein said rotor is supported and driven only at said top.
 32. The device in accordance with claim 1, wherein said rotor and said drum are arranged to form a ring chamber having a volume in a lowermost one-third which is larger than a volume in either of an uppermost one-third and a middle one-third of said ring chamber.
 33. The device in accordance with claim 1, wherein said drum is positioned substantially vertically.
 34. The device in accordance with claim 1, wherein said drum comprises circumferential protrusions extending from an interior surface.
 35. The device in accordance with claim 34, wherein said drum comprises at least two circumferential protrusions extending from said interior surface, which are axially spaced from each other, and, in a region of said rotor which corresponds to a region between said axially spaced circumferential protrusions, at least one helically arranged entraining rail is formed on said rotor.
 36. The device in accordance with claim 35, wherein said helically arranged entraining rail is arranged to form a plurality of threads.
 37. The device in accordance with claim 1, wherein a drivable rotor shaft is coupled to said rotor to rotate said rotor.
 38. The device in accordance with claim 37, wherein said rotor shaft is coupled to a bottom of said rotor, and a least a portion of said rotor shaft extends into said drum.
 39. The device in accordance with claim 38, further comprising mixing wings coupled to said rotor shaft, said mixing wings comprising a diagonal edge on a front side structured and arranged to deflect contaminants.
 40. The device in accordance with claim 1, wherein said rotor comprises a cylindrical section and conical section, wherein said conical section is arranged such that, in a direction toward said discharge opening, a gap width between said rotor and said drum increases.
 41. The device in accordance with claim 40, wherein said conical section is attached below said cylindrical section.
 42. The device in accordance with claim 1, further comprising a water feed pipe extending into an interior of said rotor, and said rotor comprising at least one water discharge hole coupled to said water feed pipe to add water to the fibrous stock between said rotor and said drum.
 43. The device in accordance with claim 42, wherein said at least one water discharge hole is arranged in a lower portion of said rotor.
 44. The device in accordance with claim 43, wherein said at least one water discharge hole is arranged in a lowermost one-third of said rotor. 